Ignition timing device for low speeds



1933- M. MALLORY ,897,703

IGNITION TIMING DEVICE FOR BOW, SPEEDS Filed 061?. 25'. 1951 takemanifold with Patented F514, 1933 UNITED STATES amen IALLOBY, 01

PATENT OFFICE IGNITION TIIIIG DEVICE FOR LOW SPEEDS Application .llledOctober 28, 1981. Serial 10. 571,005.

This invention relates to a control device for ignition timers, withparticular reference to conditions when the engine is idling oroperating at low speeds.

In order to insure a smooth and steady operation when the engine isidling, it is necessary for the timer to be set so thatthe spark willoccur when the crank is to past dead center. With such setting, when thethrottle is opened, if the initial spark advance depends primarily u n acentrifugal governor, no advance wi 1 take place until there.

has been a considerable increase in s and as a consequence the pick-upwill be s ow. On the other hand, if the spark is initially set where itshould be for the best after the throttle is opened, the idlingoperation of the engine Wlll be unsteady or perha s stopped altogether.

ith the above facts in mind, it is the object of the present inventionto provide an improved device for controlling the timing at low speedsand particularly to provide for an immediate advance of the timing whenthe throttle begins to open. With such a device, the timer may be setfor an extreme retardation of the spark when the throttle control meansis in position for idling and yet, the moment the throttle begins toopen, the spark will be advanced immediately so as to insure a quickpick-up. The subsequent control of the timing as the speed of the engineincreases may be cfiected entirely by the action of the vacuum in theintake manifold or by any of the other usual devices which have beenheretofore used. 'The present embodiment of my invention will be-moreparticularly described in connection with the accompanying drawing,which is a sectional view of the timer and in the invention associatedtherewith.

As illustrated in the drawing, the timer comprises a housing 1 withinwhich is a cam 2 mounted on the timer shaft 3 and adapted to actuate thecircuit breaker 4. Associated with the timer is an arm 5 which ismovable to and fro to advance or retard the times of i 'tion as will bereadily understood by those amiliar with the art. A rod 6 is connectedat erformance 12 in the cylinder 8 is adapted to act on the piston 7 tomaintain an extreme retardation of the timing mechanism when the engineis idling.

The throttle valve 13 is secured to a ivot pin 14 to which there is alsosecured a ever 15 which is held against a stop 16 by a spring 17 tomaintain the throttle valve in closed or idling position except when itis positively opened by other means. For opening the throttle valve acontrol arm 18 is journaled on the pin 14 andhas a connection 19 withthe accelerator. In order to open the throttle valve, the control arm 18is moved about its pivot with the lug 20 engaging the end of the ever15. The arm 18 also has a lug 21 which is connected by a rod or wire 22with the valve 11. When the arm 18 is released, a spring 23 acts on thevalve ll to close the same and at the same time to swing the arm 18 awayfrom the lever 15 as the latter engages the stop 16 with the throttlevalve 13 closed; When the throttle control arm is. released for idling,therefore, there is a lost motion of the arm 18 which must be taken upas the accelerator is again 'moved to open the throttle valve. p

From the foregoing description, it will be understood that when thethrottle control is in idling position as illustrated in the drawing,the valve 11 will be closed and the timing mechanism, then controlledentirely by the action of the spring 12, will be in its extreme retardedposition. .With the-throttle closed, even though the engine is idling,-

there will be ahigh vaccum in the intake passage 10 but, with the valve11 closed, this vacuum will have no effect upon the piston 7 and withthe maximum retardation of the timing, the idling operation willbesmooth. As the accelerator is actuated to open the throttle, the lostmotion between the arm 18 and the lever 15 will first be taken u andjust as soon as the throttle valve begins to open, the valve 11 willopen the port 9, providing a free communication between the intakeassageway 10 and the interior of the cylin er 8. The suction produced inthe passage 10 by the operation of the engine will then be communicatedto the piston 7 and will actuate the latter in opposition to the spring12 to advance the timmg and since,-with the throttle inany givenposition, the increas ng speed of the engine will cause an increasingvacuum in the intake passage, the timing will be pro essively advanced.If the throttle valve, owever, is suddenly opened wide, there will becomparatively little vacuum in the passageway 10 and there will be acorrespondingly limited advance of the timing until the speed of theengine increases and the compression in the cylinders decreases. Thisprevents a spark knock such as frequently occurs with timers asheretofore constructed, when the engine is traveling at low or moderatespeed and the throttle is suddenly o ened.

\Vhile I have described in detail the present form of the invention, itis to be understood that the same includes all such modifications thatmay fall within the scope of the appended claims.

What is claimed is:

1. The combination with an ignition timer mechanism, of a memberconnected with said timer mechanism and movable back and forth to varythe timing, a throttle valve, an arm having a connection for controllingthe throttle valve, with a lost'motion between the idling position ofsaid arm and the position where it begins to open the throttle, andmeans actuated by said arm as the throttle begins to open, to act onsaid member to ad- Vance the timing before there is any materialincrease in the engine speed.

2. The combination with an ignition timer mechanism, of a memberconnected with said mechanism and movable back and forth to vary thetiming, a throttle valve, an arm having a connection with the throttlevalve for o ening it, with a lost motion between the i ling position ofsaid arm and the position where 1t begins to open the throttle valve,and means actuated by said am as the throttle valve begins to open tocausethe vacuum in the intake passe of the engine to act on said memberto a vance the tlming before there is any material increase inthe enginespeed.

3. The combination with an ignition timer mechanism, of a pistonconnected with said mechanism and reciprocable to vary'the timing, meansoperable by itself on said lston to causemaximum retardation when t eongine is idling, a throttle valve, an arm having a connection with thethrottle valve, with a lost motion-between the idling position of saidarm and the position where it begins to openthe throttle valve, andmeans actuated by said arm, as the throttle valve to open, to act onsaid member to advance the timing before there is any material increasein the engine speed.

4. The combination with an ignition timer mechanism, ofa pistonconnected with said mechanism and pneumatically operable to advance thetiming, a cylinder'for. guiding said piston and having a port leadingfrom the cylinder to the intake passage of the engine, a valve normallyclosing said port when the engine is idling, a throttle valve, an armhaving a connection with the throttle valve for controlling the same,with lost motion between the idling position of said arm and theposition where it begins to open the throttle valve, and means actuatedby said arm to open the first mentioned valve as thethrottle valvebegins to open. 1

5. The combination withthe ignition timing mechanism and the intake.manifold of an internal combustion engine, of a member connected withsaid timing mechanism and movable back and forth to vary the timing, apassageway leading from said member to the intake manifold, a valve forsaid pa ssageway, a spring acting directly upon said valve and operableby itself to close said valve, a throttle valve, control means forsaidthrottle valve, and a connection between said control means and thefirst mentioned valve for opening the same as soon as the control ameans is actuated ,to open the throttle.

In testimony whereof I have hereunto signed my name to this secification.

' MARI N MALLORY.

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